/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.activiti.engine.impl.cmd;

import org.activiti.engine.impl.Page;
import org.activiti.engine.impl.asyncexecutor.AcquiredJobEntities;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.persistence.entity.JobEntity;

import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.List;


/**
 * @author Tijs Rademakers
 */
public class AcquireTimerJobsCmd implements Command<AcquiredJobEntities> {

    private final String lockOwner;
    private final int lockTimeInMillis;
    private final int maxJobsPerAcquisition;

    public AcquireTimerJobsCmd(String lockOwner, int lockTimeInMillis, int maxJobsPerAcquisition) {
        this.lockOwner = lockOwner;
        this.lockTimeInMillis = lockTimeInMillis;
        this.maxJobsPerAcquisition = maxJobsPerAcquisition;
    }

    public AcquiredJobEntities execute(CommandContext commandContext) {
        AcquiredJobEntities acquiredJobs = new AcquiredJobEntities();
        List<JobEntity> jobs = commandContext
                .getJobEntityManager()
                .findNextTimerJobsToExecute(new Page(0, maxJobsPerAcquisition));

        for (JobEntity job : jobs) {
            if (job != null && !acquiredJobs.contains(job.getId())) {
                lockJob(commandContext, job, lockOwner, lockTimeInMillis);
                acquiredJobs.addJob(job);
            }
        }

        return acquiredJobs;
    }

    protected void lockJob(CommandContext commandContext, JobEntity job, String lockOwner, int lockTimeInMillis) {
        job.setLockOwner(lockOwner);
        GregorianCalendar gregorianCalendar = new GregorianCalendar();
        gregorianCalendar.setTime(commandContext.getProcessEngineConfiguration().getClock().getCurrentTime());
        gregorianCalendar.add(Calendar.MILLISECOND, lockTimeInMillis);
        job.setLockExpirationTime(gregorianCalendar.getTime());
    }
}